Same problem here. SH 5, Play SH5 and Ubisoft game launcher are on my winxp firewall exceptions, but it won´t help. "an internet connection is required to play this game. failed to connect to the ubisoft masterservers etc" appears and game won´t start. Internet works fine. Has someone resolved this?

I'm trying to track down port numbers that might be required to be open, but have any of you using a router getting this error tried setting the router into a DMZ? If, not try doing this, but only do this before entering the game and turn off DMZ once you're finished with the game since it will open you up to the internet entirely. Also, if any of you are able to connect directly into modem (bypassing the router) and try it, let me know if you get the same error.

Is Ubisoft serious?
moving PC to a DMZ in order to get the DRM to work?
that's like sayong you can buy a car form us but to get it to run you must first remove all safety features such as airbags, seat belts etc then push car downhill into oncoming traffic... then it may work!
that is a f*****g joke Ubisoft.